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PLCs for Beginners

You're reading from   PLCs for Beginners An introductory guide to building robust PLC programs with structured text

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Product type Paperback
Published in May 2024
Publisher Packt
ISBN-13 9781803230931
Length 380 pages
Edition 1st Edition
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Author (1):
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M. T. White M. T. White
Author Profile Icon M. T. White
M. T. White
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Toc

Table of Contents (25) Chapters Close

Preface 1. Part 1: Basics of Computer Science for PLC Programmers FREE CHAPTER
2. Chapter 1: Computer Science Versus Automation Programming 3. Chapter 2: PLC Components – Integrating PLCs with Other Modules 4. Chapter 3: The Basics of Programming 5. Chapter 4: Unleashing Computer Memory 6. Chapter 5: Designing Programs – Unleashing Pseudocode and Flowcharts 7. Chapter 6: Boolean Algebra 8. Part 2: Introduction to Structured Text Programming
9. Chapter 7: Unlocking the Power of ST 10. Chapter 8: Exploring Variables and Tags 11. Chapter 9: Performing Calculations in Structured Text 12. Chapter 10: Unleashing Built-In Function Blocks 13. Chapter 11: Unlocking the Power of Flow Control 14. Chapter 12: Unlocking Advanced Control Statements 15. Chapter 13: Implementing Tight Loops 16. Part 3: Algorithms, AI, Security, and More
17. Chapter 14: Sorting with Loops 18. Chapter 15: Secure PLC Programming – Stopping Cyberthreats 19. Chapter 16: Troubleshooting PLCs – Fixing Issues 20. Chapter 17: Leveraging Artificial Intelligence (AI) 21. Chapter 18: The Final Project – Programming a Simulated Robot 22. Assessments 23. Index 24. Other Books You May Enjoy

Memory addresses

Up until this point, we have explored the types of memory and memory devices. However, what we have not explored is how memory works. As such, this section is going to be dedicated to exploring how memory works.

How memory works

Conceptually, memory can be visually represented by Figure 4.1:

Figure 4.1 – Computer memory representation

Figure 4.1 – Computer memory representation

Computer memory can best be thought of as tiny sections that compose the overall memory system. In the case of Figure 4.1, each memory square is a memory block. That is, each square will hold a piece of data such as the number of parts to make or the state of the machine.

Each memory block has an address that is used by the PLC to organize and keep track of the memory locations. In the case of Figure 4.1, the address is the alphanumeric label in the diagram. When data needs to be retrieved, the computer or PLC will invoke the memory address and retrieve the value. On the flip side of that...

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